Options for Making Greek Yogurt Dairy Processors Can Make High-Protein Yogurts with Various Ingredients, Processes and Equipment
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Options for making Greek yogurt Dairy processors can make high-protein yogurts with various ingredients, processes and equipment. What's best? That's a hard question to answer because the options have their own pros and cons. n the las t five yea rs, G reek yogurt has mented milk is passed thro ugh a specially One key advantage ofa "no whey separa gone from 1% to 36% sha re of the designed separator to co ncentrate the tion" approac h is that it is now amenable to total yogu rt market. Some estimate coagulated solids. Up to two-thi rd s of the either cup set or bulk set yogurt manufac I Greek yogu rt and related products will original milk vo lume is removed to ac hieve ture. Fu rther, co nstituents such as calcium, account for more than 50% share of market the degree of protein concentration desi red. which become more soluble in the acidic in th e nea r future. But the large volume of acid whey th at has conditions of yogurt, are all retai ned si nce Many attribute the rise to consumers' been removed represents a challenging by there is no drainage step. preference for the product's highe r-protein product stream for manufacturers to utili ze Depe nding on the protein ingredient(s) content as well as the associated th icker and or treat as a waste stream. used, they can impact ferm entation times. creamier texture. The gradual reduction of Ultrafiltrati on also has been shown to You may need to change the cultures used as milk solids and acidity in traditional (non be effective to conce ntrate the fermented some yogurt microorganisms may not grow co ncentrated) yogurts which makes them milk. After fermentatio n, the yogurt is as well under the higher solids conditions. more like pudding cups could have been heated to approximately 120F, passed Additionally, these ingredients increase the tipping point that made consumers thro ugh a multistage ultrafiltration sys the buffering capacity of the system; hence more receptive to a price/value relationship tem , cooled and packaged. Nearly all the more acid needs to be developed to achieve associated with the highe r-cost, higher milk proteins are retained (including the same pH of typical yogurt. These factors protein introductions. those soluble whe y pro teins no t associated can result in longer fermentation times and In reality, these types of high dairy-pro to caseins by a heat treatment) because the a more acidic taste in the finished product. tein (high total milk solids) yogurts have pore size of the membrane is too small for However, the fact that this approach results been around for a long time and are known whey proteins to pass into the permeate. in essentially no by-product is very attrac in different parts of the world as labneh, However, m embrane fouling can reduce tive, and essentially no additional eq uipment ymer, skry, basa, torba, syuzma, mastou, filtration ra tes a nd increase cleaning costs. is needed to make this product in existing zabady, chakka and ititu. The permeate from this process remains cultured products facilities. Here in the Un ited States, higher-protein problematic because it is a dilute lactose yogurts have come to be known as Greek solution that has a high mineral content, The best choice? yogurt. There is no legal standard to define low protein content and a low pH . There are pros and co ns to all the approaches a m inim um protein co nte nt or distinct Vacuum evapora tion or reverse osmo in producing higher-protein yogur ts. There manufacturing process for it. No netheless, sis also have been explored to remove only really is no simple answer to what is "best:' Greek yogurts typically have protein con water from the fermented milk mixture Further, there may be unanswered ques te nts ranging from 6% to 12%, or about 1.5 and concentrate all the fermented milk sol tions abo ut h igher protei n (or high er solids to 4 times that of traditional yogurt. ids. While these approaches res ult in clean yogurts) that require more investigation; for by-product streams (water), any residual example, how do specific pro biotic bacteria Concentrating protein lactose in the fermented milk is also con survive in this product? Some argue that the only way to make centrated and hence the ratio of protein In the end, consumers will continue to seek Greek yogur t is by straining the cultured to-lactose in the fin ished product is lower the price-value relationship that reflects their milk m ixture (yogurt) through a cloth bag than the ratio using the other processes desire for taste, nutrition and convenience. to concentrate the cultured milk coagu mentioned above. Don't lose sight of the fact that while we lum. Sometimes mild pressure is applied debate what Greek yogurt is or is not, soy to shorten the draining time. The process Increasing protein processors will launch higher-protein fer is simple and requires minimal investment Higher-protein yogur t also ca n be mented products of their own in an attempt in eq uipment. However, com plete strain achieved through formulation prior to fer to lure consu mers. • ing can ta ke from six to 18 ho urs. T his can mentation. Protein in the milk mixture can have a negative impact on shelf life and is be increased by the addition of dair y pro Phillip S. Tong is Professor of Dairy not feasible for large-scale operations. tein-based ingredients (that is, whey pro Science and Director of the Dairy Products More typically, concentration is achieved tein concentrate, milk protein conce ntrate, Technology Center at California Polytechnic by using a centrifugal separator. The fe r nonfat dry milk or sodium caseinate ). State Un ivers ity. 28 Dairy Foods I May 2013 .